Thursday 16 April 2009 19.01 EDT
First published on Thursday 16 April 2009 19.01 EDT

It's one of the UK's greatest independent labels, responsible for introducing the world to Aphex Twin, LFO, Boards of Canada and Squarepusher. But the origins of Warp Records, which celebrates its 20th birthday this year, were much humbler. The track that would inspire a revolution in UK dance music was conceived in a teenager's bedroom.

In 1989, George Evelyn was already a music veteran, having made his first track aged 14. Together with his pal Kevin Harper, he ran a club night in Leeds called Downbeat, where they would play a mixture of rare groove, hip-hop and dance. When they heard primitive British electro tracks such as A Guy Called Gerald's Voodoo Ray, they decided to make their own music, creating a bleepy track called Dextrous using a bedroom-based sampler. Having failed to spark much interest from record labels either here or in the US, they pressed up a white-label single and took it around record shops. One of those was Fon, an independent retailer in Sheffield run by Steve Beckett and Rob Mitchell. The pair decided to help Harper and Evelyn - now calling themselves Nightmares On Wax - by setting up a label.

Two decades later, Dextrous is remembered as a seminal British dance track, while the label has become a pioneer of sorts. The name Warp is synonymous with electronic music but has a cultural reach stretching into guitar music and film. This summer, Warp celebrates its platinum anniversary with events around the world, which must have seemed the stuff of fantasy when Beckett and Mitchell started with the aid of a £40 Enterprise Allowance grant.

Their first release, Track With No Name by Sheffield techno outfit Forgemasters, was distributed in a borrowed car. But with the Nightmares On Wax track, everything exploded. Evelyn remembers being in a rave in an abattoir in Blackburn when he saw the dancers' frenzied reaction. "My spine went cold," he says. "It felt like a revolution."

Dextrous sold 30,000 copies and made the top 75. It might have gone higher had Warp not been a rather hapless operation."We didn't realise at first that for a single to qualify for a chart position, you have to have a barcode on it," says Steve Beckett, laughing. "Duh!"

Initially, Beckett says he was just glad to have another excuse "not to get a proper job", but he got more involved in Warp, conceiving it along the lines of Factory Records: a northern-based independent, with profits shared 50/50 between artist and label. Sheffield firm Designers Republic created a distinctive purple Warp record sleeve, which became synonymous with the sound known as "bleep". This minimal, funky techno re-energised Sheffield's electronic-music history, which had been all but seen off by Def Leppard's 1980s glam metal.

"I'd stopped going out," says Richard H Kirk, who had been in Cabaret Voltaire before creating an early bleep hit for Warp under the name Sweet Exorcist. "But suddenly you were getting white kids, black kids and Asian kids in the same clubs, because of the dub element. It rejuvenated Sheffield."

Those early Warp releases even sounded like Sheffield. "You'd drive through and see Forgemasters steelworks," says Beckett. "You'd almost see sparks and hear anvils clanging." Warp didn't need to look for acts: the music was around them. People would run up to Beckett in clubs, saying, "I've done a bleepy tune, I'll bring it in on Tuesday."

But with Warp's fifth release, Beckett realised that his emerging operation could have a major effect on the industry. LFO by LFO ("low frequency oscillator") sounded like an avant-garde collision of Kraftwerk and Detroit techno, but it was the product of two teenagers who invented a hugely influential, bass-heavy form of techno in a bedroom in Leeds. With "vocals" from a Speak & Spell toy, the track erupted over eardrum-bashing sub-bass, which, Beckett admits, made it unplayable on the radio. Nevertheless, they sold 130,000 records to clubbers hypnotised - or deafened into submission - by the boom.

"There's a website now listing tracks that should never have been released, and LFO's in there with The Birdie Song," sniggers Beckett. "Which of course, is exactly what you want." While clubbers danced away their tinnitus, LFO reached No 12, causing baffled DJs such as Radio 1's Steve Wright to resort to playing cow noises over the music. Beckett was thrilled: "It felt like Djs were losing control." Warp's next act of subversion was to wind up Pete Tong by declaring that bleep was dead and that the future of music was "clonk" - the title of Sweet Exorcist's next 12in. "He went for it," says Beckett with a laugh, sounding less like a record mogul and more like a naughty schoolboy.

Beckett has headed Warp since Mitchell's death from cancer at the age of 38, in 2001. He wears comfortable trousers and is as far from the geeky, techno image of his label as it's possible to imagine. "The first record I bought was Gudbuy T' Jane by Slade," he says. "I only discovered electronic music when we got a dance section in the shop." However, his indie-rocking past was crucial to Warp's development, as they outflanked rivals by using rock techniques to sell dance music: they made efforts to have their acts named in NME, and bands were encouraged to tour - not always with success.

"LFO started fighting on stage," says Beckett. "They were slamming keyboards into each other's heads, citing 'the pressure'. This was after three gigs." Unsurprisingly, LFO fell apart; the band's Mark Bell has since become Björk's producer.

But Warp were once again in the right place at the right time as electronic music slowed down in the 1990s. Kirk recalls how things changed after the success of the Orb, who initially recorded for Sheffield label Wau!. People starting sending Warp tapes that "weren't really floorfillers, but almost by accident had become something else". When Beckett put acts like B12 and Plaid on an album called Artificial Intelligence, "electronica" was born. The genre turned a generation of rock kids on to electronic music, especially in the US, where, when Aphex Twin toured the States with Orbital and Moby, "it went totally insane," Beckett recalls.

He is reluctant to name his most important signing, but admits that Aphex Twin (real name Richard James) is "up there". The godfather of ambient techno sold 1m Warp records, including 1999's notorious Windowlicker, whose sleeve featured an unforgettable image of James's grinning face pasted on to a female model's body. But subsequently, the maverick creator has virtually disappeared. Warp is hoping he might produce an album later this year, but Beckett can understand why James has seemingly wrecked his own career. "He's the person the least interested in the music business I've ever met. He has no comprehension of why you would do anything to please anybody else."

In recent years, Warp have faced a wider problem. Thanks to the resurgence of guitar bands, says Kirk, the bottom has fallen out of the market for electronica. Beckett insists he was getting bored with it as well. "I didn't want to end up doing Now That's What I Call Artificial Intelligence," he says, explaining the thinking behind signing different types of electronic acts, such as Andrew Weatherall's dub outfit Sabres of Paradise and Birmingham psychedelicists Broadcast.

However, when Warp signed Newcastle guitar band Maxïmo Park, purists were up in arms. "Everyone went, 'How dare they?!'" says Beckett. He points to Warp's roots in an indie record shop and suggests he has always just wanted the best music. That enthusiasm led Maxïmo Park to opt for Warp over majors who wanted to change their sound, as singer Paul Smith explains: "They'd say stuff like, 'You could be the new Radiohead if you did this.' We were worried about what was going to happen to our songs."

Warp has also had great success with its move into films. Director Shane Meadows had been considering giving up film-making after his experience with his 2002 movie Once Upon a Time in the Midlands: "I was sick of bigger budgets and more pressure." But the fledgling Warp Films offered another way. Like the music arm, its origins were strictly DIY: "Mark was producing from his garden shed, and the film crew fitted in a minibus," recalls Meadows. Warp wanted him to make a feature film in the same style as he had made his early shorts: quickly and spontaneously, with no script.

The first Warp film, Meadows's Dead Man's Shoes, was made with Lottery funding, and won a Bafta nomination. And his movie This Is England took 2007's best British film Bafta. Meadows says he has found a lifelong home at Warp, even though he doesn't like all the label's music. "Some of it sounds like someone falling down the stairs with pots and pans." he says. "But if they like it, they back it, whether it sells 100,000 copies or 1,000. Warp believes in artists."

The electronic-music producer, who died last week, was an innovator of electronic sound, from his huge influence on the early club scene to Radiohead remixes and groundbreaking collaborations with Björk